Fuel injection pump



Jan. 15, 1952 G. c. DROUOT 2,582,535

FUEL INJECTION PUMP Filed April 7, 1949 4, Sheets-Sheet} 23 39 g 42-2 gJ 52 13 I? 5! 1/ 36 a g II I H I! d I 22 5 AL I INVENTOR 645mm O//7RLLS020007;

I Q I M ATTORNEY Jan. 15,1952 y I .5. 'DROUOT 2,582,535

UEL INJECTION PUMP Filed April 7, 1949 4 sheets-sheet 2 Z3 Q INVENTOR64.5w Cl/fl/PLEIS 0/?0007;

ATTORNEY Jan. 15, 1952 c, DROUOT 2,582,535

FUEL INJECTION PUMP Filed April '7, 1949 4 Shets-Sheet 3 A Q P 3 1' 1 7\I I' 7 8 w 71 6 INVENTUR ATTORNEY Jan. 15, 1952 G. c. DROUCT FUELINJECTION PUMP Sheets-Sheet 4 Filed April 7, 1949 V "nvvsmon 6/7670OJJIPL ES 053000 M ATTORNE? Patented Jan. 15, 1952 I 2,582,535 FUELmmc'rron PUMP Gaston Charles Drouot, Paris, France, mlgnor to Society"La Precision Mecanlque," S. A., Paris, France, a society of FranceApplication April 1, 1949, Serial No. same In France April 14,

12 Claims. 1

The present invention relates to piston machines, and especially topumps (as it will be supposed in the following description), and it ismore particularly, but not exclusively, concerned with pumps for theinjection of fuel into internal combustion engines, in particularmulticylinder engines.

Its chief object is to provide a pump of this kind which is betteradapted to meet the requirements of practice than those used up to thepresent time, and in particular which is'of simpler construction.

According to my invention, in a pump the piston of which is adapted toreceive, concurrently with axial translatory displacements, a rotationmovement with respect to its cylinder, so as to permit in particular ofdistributing fuel to a plurality of distinct orifices or conduits, therotary movement of this piston is imparted thereto from the outsidewhereas means are provided in the pump, in particular cam means, forobtaining from this rotary movement the above mentioned axialdisplacements.

Other features of my invention will appear in the course of thefollowing description of some embodiments thereof, given merely by wayof example, and in which:

Figs. 1 to 5 show respectively in axial section, in part sectionanalogous to Fig. 1 but showing a regulating member in a position ofadjustment different from that of Fig. 1, in top view, and in section onthe lines IV-IV and V-V of Fig. 1, a fuel injection pump for afour-cylinder engine made according to my invention;

Figs. 6 and '7 are two diagrammatic sections in planes transverse to thepiston axis of such a pump, for distribution to three distinct conduits,and according to two different embodiments;

Fig. 8 is a part axial section of a pump of the same kind made accordingto another embodiment of my invention;

Figs. 9 to 11 show respectively in diagrammatic and part section, intransverse section on the line X-X of Fig. 9 and in plan view on theline XI-XI of Fig. 1, an injection pump embodying various other featuresof my invention.

My invention will be described as applied to a pump for deliveringliquid into several distinct conduits, in particular for injecting fuelinto the respective cylinders of a multi-cylinder internal combustionengine.

First, it sh nldbe reminded that the pumps of this kind generallyinclude as-many pump bodies (and pistons, valves, cams, push-pieces,etc.) as

there are cylinders be supplied. This necessitates a multiplicity ofparts which, in addition to the high cost of the whole, are liable to befrequently out of adjustment, due to the lack of total similitudebetween these various parts. On the other hand, regulation, 1. e.measurement of the amounts of fuel injected in accordance with thedesired speed and power to be obtained, is generally ensured by amechanical or pneumatic regulator which acts upon the adjusting means ofsaid pumps; but, due to the multiplicity of these means. the effort thatis required is considerable and consequently necessitates big and costlyregulators. 7

It is known that there are also piston pumps in which the piston movesboth axially and in rotation, in order to ensure by means of the samepiston fuel delivery toward several distinct conduits, but theirconstruction is relatively complicated and requires a lot of room.

According to my invention, the pump includes a piston of this kind,having both an axial and a rotary displacement, cooperating with severaldelivery conduits, this piston receiving its rotary movement from adrivingshaft whereas means are provided, in the pump, for obtaining thedesired reciprocating movement of the piston for predetermined angularpositions of said shaft.

These last mentioned means advantageously include a kind of crossbarprovided at its ends with cams adapted to cooperate with abutmentelements, such as rollers, carried by a fixed plate or disc, which maybe adjustable.

For instance, my pump includes a shaft i running in at least onesuitable bearing of the pump frame 2 and which drives. through a fork 3,a crossbar 4 capable itself of driving the rod 5 of the piston 6 of saidpump. This crossbar is provided at its ends with cams of suitableprofile 1 cooperating with a cam track or race 8 on which are providedparts 9 capable of producing the axial translatory movement, the wholebeing subjected to the action of return spring Ill. These last mentionedparts 9 are advantageously constituted by balls or rollers mounted insuitable housings of plate II which carries said cam track.

It will be understood that, according to the number and position of theabutment means 9, it is possible to adjust in a suitable manner the'number and angular position of the piston strokes for every revolutionof the shaft, in accordance with the number of cylinders to be fed.

Preferably, I provide, between crossbar 4 and the rod 5 of the piston tobe driven, a connec- 7 3 tion which gives the crossbar (which, besides,is guided by fork 8) some relative freedom. this connection beingconstituted by any joint of a known type and including for instancea'disc Ill 'carried by rod I and provided on its periphery with teeth IIadapted to engage in the notches of a disc I! carried by crossbar I,which a centering at 63, the whole being held in contact by spring I0.In this way. I ensure a perfect contact between the two cams I and theirrollers.

As for the means for ensuring distribution of the liquid or fuel towardthe outgoing conduits such as I2, they may be of the most differentkinds, one of the embodiments that may be adopted'consisting, as shown,in causing a lateral passage I3 formed in the piston to cooperate withtwo ports such as I4. I5 leading to conduits I8. I] intended to connecteach conduit I2 with the delivery chamber I8 of the pump body. There maybe provided a single conduit I3, and also a single port I4. whichcooperates also with a circular groove ll of the piston.

In the case shown by Figs. .1 to 5, where the pump is intended to supplytwo or four outgoing conduits I2, the roller carrying disc II carriestwo pairs of rollers diametrally opposed, the piston being supposed .tobe provided with only one lateral passage I3 and rotating at the rate ofone revolution per cycle of the engine. In the case of six outgoingconduits, in particular for a six cylinder engine, six rollers would beprovided at 60 from one another.

If it were desired to supply an engine having an odd number of cylinders(1, 3, 5, etc.), I would for instance provide the piston, supposed torotate at one half of the engine speed, two distributing passages suchas I31 and I3: (Figs. 6 and 7), and provide a number of rollers 9 equalto 2, 6 or 10, disposed by pairs diametrally opposed at 120, 80 or 36,the outlets toward the different cylinders being:

Either distributed over one half of a circumference, the same passageI31 or I32 comin successively opposite the orifices of conduits I2 or I!during one engine cycle (Fig. 6),

Or uniformly distributed around the whole periphery of the pump body,the diametrally opposed passages I31, I32 passing alternately before theoutflow orifices (Fig. 7)

For an engine having two cylinders at 90, ring II will be provided withtwo pairs of rollers at 45 from each other, the pump running at one halfof the engine speed and the piston being provided with two passages I31,I32.

It should therefore be noted that, whatever be the number andarrangement of the engine cylinders, it will always be possible toensure a correct distribution thereof.

I have illustrated, in particular, on Figs. 8 to 11, other arrangementswhich may be used in some cases, in particular for ensuring correcttiming of the various injections with respect to the engine cycle.

It has been seen above that, due to the symmetry of the two cams carriedby the crossbar and to the corresponding symmetry of the rollers, everyupward movement of the pump piston is necessarily repeated after thepiston or the crossbar has rotated through 180. This will generally makeit necessary to have the pump running at a speed different from that ofthe engine.

In order to remedy this drawback, according to the embodiment of Fig. 8,the rollers, that is to say in the present case, those of each pair, aredisposed in a non-symmetrical manner with respect to the piston axis, sothat the cross bar is causedto contact them only once per revolution.

It will be seen on Fig. 8 that the two cams I of the crossbar, which arethemselves disposed in dissymmetrical fashion with respect to the pistonaxis, are acted upon by the rollers only once per cycle, that is to sayonce per revolution of 360. This is due to the fact that, after arotation of 180, cams I no longer meet with rollers but remain incontact with track 8, due to the above mentioned dissymmetry.

Such an arrangement is particularly advantageous, not only because itpermits of adopting for the speed of the pump the same value as for theengine. but also because it permits of adapting the pump to all kinds ofengines whatever be the number of cylinders, since it is possible todispose the different pairs of rollers 3 along diameters disposed at thedesired angles.

According to the arrangement of Figs. 9 to 11, I can maintain thesymmetry of the cams and rollers (although this is not necessary), owingto the fact that means are provided for enabling the piston, for some ofits upward movements, not to deliver fuel.

I may proceed, for this purpose, in different ways, and in particularprovide the piston with suitable channels, as it will be hereinafterexplained.

For instance (Figs. 9 to 11), considering the distributing head 6 ofpiston 5, which is intended to cooperate with one or several intakeorifices 2I, this head may be provided with at least one lateral channelBI arranged in such manner that it can come opposite said orificesduring the corresponding upward movement.

Supposing for instance that it is desired to inject fuel into a twocylinder engine requiring injections at intervals, the pump such asdescribed with reference to Fig. 1 with two pairs of opposed rollers 9at 90 will make it possible to solve the problem, provided that the headof piston 6 includes a lateral channel 6I adapted to cooperate with twointake orifices at 90 to each other.

In this way, two of the upward strokes of the piston, corresponding tothe passage of channel 6I opposite orifice 2 I will be inoperative,whereas the two other strokes, occurring at 90 to each other, willpermit of ensuring correct injection.

The same method might be used for injecting fuel into engines having onecylinder, or two cylinders at 90, or three cylinders at 60 or or fivecylinders, etc.

However, it may be advantageous to make use, in particular when thenumber of cylinders is still higher, of another feature of theinvention, according to which the roller carrier I l is driven with acontinuous movement of rotation in a suitable direction and also at asuitable speed.

In particular, crossbar 4 might be driven in one direction at a speed Vand roller carrier 8 in the opposed direction, with a different speed v(Fig. 9). All means may be used for this purpose, such as screw gears 60or the like.

Besides, it should be well understood that the possibility of movingroller carrier II might be provided for other purposes, in particularfor adjusting the lead to injection. In this case, the roller carrierwill not be driven in a continuous manner, but will be merely adjustablein position.

As a matter of fact, as well known, it is often useful, for the goodoperation of engines at different speeds, to be able to vary thebeginning of injection with respect to the engine cycle.

As a rule, this result is obtained by a controlled or automaticmodification between the pump drive and its cam shaft operation, in thecase of pumps ofcurrent types.

In a pump such as above referred to, the same result is obtained, in amore simple manner, by shifting roller carrier II in the suitabledirection; in this way, cams 1 will act upon rollers 9 with the samephase difference and the beginning of the injection will thus be changedwith respect to the engine cycle.

Concerning now the supply of liquid or fuel to the compression chamberof piston 6, it may be ensured in any suitable manner, prefer-v ably sothat said piston, according to the commonly used arrangement, controlsitself the inflow and discharge of the fuel, in cooperation with atleast one orifice 2| in communication with a feed chamber 22. Besides,it should be noted that the surfaces of the piston acting as valveelements, such as shown at 23, 24, on Fig. 1, and which are supposed tobe plane and at right angles to the piston might be oblique and carriedby a head 6 rotatable with respect to the rod 5 of the piston, so as tobe adjustable in angular position for varying the feed rate and/or thelead or end of injection. This adjustment might be controlled throughall means of the known type adapted to modify the relative angularpositions of two rotating parts.

Preferably, according to an advantageous arrangement, cams 1, theprofile of which can be given any suitable shape (possibly adjustable),will be adapted to ensure, during the first portion of the piston stroke(which corresponds to closing of orifices such as 2! and to the building up of pressure) an accelerated movement, while on the contrary themovement will be given a more moderate speed during the subsequentstroke portion corresponding to normal injection. As a matter of fact,during the first stroke portion and since the fuel is not yet underpressure, the energy required from the cam is used only for providingacceleration of the masses in movement. Furthermore, when there is madeuse of a regulating device including a movable valve member as will behereinafter described, this acceleration is, at it will be seen,advantageous for increasing the rate of injection at low speedscorresponding to the starting of the engine.

The obtainment of suitable profiles for these conditions of operation isparticularly easy in the case of cams moving with a translatory motionby cooperation with abutments or rollers 9, as it is the case. On Fig.5, I have differentiated the zones 12 and b along which this profileproduces, respectively, a quick upward movement and then a slower upwardmovement of piston 5, 6.

According to another feature of my invention, the pump is provided witha single regulating device constituted in the form of a valve memberinterposed between compression chamber 20 and delivery chamber l8. Thisvalve member 25, movable in a bore 26 interposed between said chambers,is in particular provided over aportion of its length with at least onelateral channel 21 adapted to permit the flow of fuel therethrough forsome of the relative positions of member 25 along the axis of bore 26,which positions are determined by the hydrodynamic pressures or by theeffects of inertia, to ensure the 6 desired regulating action as statedin said pat- This adjustment is made possible by the fact that I providefor the possibility of varying at least one of the active heights suchas h and d which represent, in the. position of rest of the valve membersubjected to the action of its spring 28, respectively the free heightof channel 21 extending in chamber 20 and the distance between the upperedge of said channel and the seat of the valve member.

In the embodiment that is shown, where two channels 21 and 211 areprovided, height h is made variable at will by making valve member 25rotatable about its axis, through a control member 29, and by causingthe lower end of channels 21, 211 to cooperate with an oblique edge 30which constitutes the outlet of bore 2' into the compression chamber.

This oblique edge 80 is for instance carried by an intermediate piece 3|held on the pump body through any suitable means, for instance by meansof a cap kept in positionby a nut I3.

The device works in the following manner. In the relative positionillustrated by Fig. l, which corresponds to the starting of the engine,with the feed of a supplement of fuel, channel 211 is cleared at itslower end by oblique edge 80, whereas, on the contrary, channel 21cannot open simultaneously into chambers 20 and 18 (It being thensmaller than (1). If the pump and the engine run very slowly, the wholeof the fuel fed by piston 6 is caused to flow through channel 211, valve25 being slightly lifted above its seat. The height over which channel211 opens into compression chamber 22 is calculated in such manner thatthe speed of the engine is limited to a value lower than the possibleutilization speed, for the flow of fuel is stopped as soon as said speedtends to be exceeded since the valve member is then driven into itsboreand the flow of fuel is accordingly reduced to zero by the fact thatliquid is subsequently sucked back, during the return stroke of thevalve member, from delivery chamber l8.

When the engine has started running, control member 28 is rotated, tobring the regulating valve member 25 into a position such as that shownby Fig. 2, where the super-feeding channel 211 no longer comes to openinto chamber 20 and can no longer serve to the flow of fuel. On

the contrary, channel 21, intended for normal operation of the engine,is then sufficiently cleared to permit the flow of fuel therethrough,but the output that is then obtained is always reduced by the amount ofsucked back liquid which corresponds to distance d, which shows thatthis distance it corresponds to a supplementary feed for starting.

When the control member is more or less rotated, the useful height (h-d)of channel 21 can be varied, and also, consequently, the limit speed forwhich the valve member, in the position of Fig. 2, is caused to moveinto its bore and thus to stop the flow of fuel through said channel,and therefore to limit the speed.

The choice, for cams such as Let a profile of the kind of that abovespecified, i. e. permittin an acceleration at the beginning of thestroke of piston B, 6, is particularly advantageous for the operation ofthe regulating device above described.

As a matter of fact, the beginning of the stroke corresponds, during thestarting period, to the injection of the supplement of fuel feed throughchannel 211 the rate of which injection it is of interest to accelerate,in view of the fact that the engine is then running at low speed. On theother hand, during normal operation, this stroke takes place without adelivery pressure of any appreciable value, because it corresponds tothe inward movement of valve member 25 which compensates for the volumeof resucked liquid corresponding to 11, so that acceleration has nodrawback, despite the higher speed of the engine. Normal injection takesplace only after the valve member hasbeen moved in a distance equal to dand the portion a of the cam profile has already been left behind, sothat piston I is urged to move at a more moderate speed.

According to another feature of my invention, in order to ensure acorrect filling of pump body 20 in the lower position of piston 5,through orifice or orifices 2|, a suitable pressure is provided in feedchamber 22, this pressure being advantageously obtained by means ofpiston 5 itself, which acts as a feed pump for a suitable chamber orcasing.

Fig. 1 shows a preferred embodiment of the above mentioned feature,according to which the lower portion of the pump body, which containsthe piston driving means, is made in the form of a fiuidtight chamber 34communicating on the one hand with the fuel intake 5 through an inletcheck valve and on the other hand with chamber 22 through a deliverycheck valve 31 and a conduit 38.

The reciprocating movement of piston I produces, in chamber 34, apump-like action, which can thus feed annular chamber 22 with fuel atthe desired pressure. However, as the periods of delivery of this pumpare not exactly in phase with the periods of filling of the upper pumpbody, it is advisable to fit chamber 22 with a small elasticaccumulator, constituted for instance by a piston 39 subjected to theaction of a spring 40, this piston being adapted to open a by-pass 4| inits rear position, in case of excess of fuel feed.

Of course, the valves, the accumulator and the by-pass may be combinedtogether, and include diaphragms of other members capable of ensuring acorrect and regular working.

Such a pump has many advantages, in particular:

A greatly reduced number of parts, in particular in the case of aninjection pump for a multicylinder engine,

Greatly reduced overall dimensions due to the fact that the feed pump isincorporated in the pump body proper, when this arrangement is used,

And the possibility of easily varying the conditions of operation of theregulating device while ensuring a high reliability of operation of thisdevice.

In a general manner, while I have, in the above description, disclosedwhat I deem to be practical and emcient embodiments of my invention, itshould be well understood that I do not wish to be limited thereto asthere might be changes made in the arrangement, disposition and form ofthe parts without departing from the principle of the present inventionas com- 8 prehended within the scope of the accompanying claims.

What I claim is:

l. A piston pump which comprises, in combination. a frame, a pump bodyrigid with said frame, a piston both rotatable and slidable axially insaid body, a driving. shaft, a crossbar extending on either side of theaxis of said piston operatively connected with said piston, joint meansfor coupling said piston with said crossbar with a limited amount offreedom, at least two cams carried by the respective ends of saidcrossbar, a fixed race carried by said frame adapted to cooperate withsaid cam, spring means for urging said cam against said race, and atleast two rollers journalled in said race with their respective axeslocated along different diameters of said race and adapted to cooperatewith said cams for causing said piston to move axially against theaction of said spring means for at least one predetermined angularposition of said piston with respect to said body.

2. A piston pump which comprises, in combination, a frame, a pump bodyrigid with said frame, a piston both rotatable and slidable axially insaid body, a single external means for rotating said piston about itsaxis with respect to said body, two elements, one coupled in rotationwith said piston and the other carried by said frame, one face of one ofsaid elements being at right angles to said piston axis and forming atleast one circular race the center of which is on said axis, at leasttwo rollers journalled in said race with their respective axes locatedalong different diameters of said race, said rollers projecting from thesurface of said race, and cam means rigid with the other of saidelements and located in a single axial plane thereof arranged tocooperate with said race and said rollers for causing said piston tomove axially every time said cam means run on said rollers.

3. A piston pump according to claim 2 in which said cam bearing elementis coupled in rotation to said piston.

4. A pump according to claim 3 and means for rotating said race aboutsaid piston axis with a speed of revolution different from that of saidpiston.

5. A pump according to claim 2 further including means for preventingoperation of said pump for at least one of said axial translatorymovements of the piston in every cycle.

6. A pump according to claim 2 in which said pump body is provided withat least one liquid intake orifice, valve means carried by said pistonfor controlling inflow of liquid from said orificc, said piston beingprovided with at least one lateral longitudinal passage in theperipheral wall thereof to prevent operation of said pump for at leastone of said axial translatory movements of the piston in every cycle.

7. A pump according to claim 2 in which said race is adjustableangularly about the piston axis.

8. A pump according to claim 2 in which the profile of said cams isdetermined to produce first a quick upward movement of the piston andthen a slower movement.

9. A piston pump according to claim 2, and spring means urging said twoelements together in an axial direction.

10. A piston pump according to claim 2, means forming a compressionchamber in said pump body, said piston being slidable and rotatable insaid compression chamber, means forming a decompression chamber.

11. A pump according to claim 10 further including means for adjustingthe operation of said regulating valve member.

12. A piston pump which comprises, in combination, a frame, a pump bodyrigid with said frame, a piston both rotatable and slidable axially insaid body, a single external means for rotating said piston about itsaxis with respect to said body, two elements, one coupled in rotationwith said piston and the other carried by said frame. one face of one ofsaid elements being at right angles to said piston axis and forming atleast one circular race the center of which is on said axis, at leasttwo rollers journalled in'said race with their respective axes locatedalong different diameters of said race, and cam means constituted by twocams rigid with the other of said i elements and located on either sideof said piston axis in the same axial plane arranged to cooperate withsaid race and said rollers for causing said piston to move axially everytime said cam means run on said rollers.

GASTON CHARLES DROUOT.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,951,340 Boh'nslav Mar. 20, 19342,286,928 Pipkin June 16, 1942 2,351,908 Beeh June 20, 1944 2,391,174Townsberry Dec. 18, 1945 FOREIGN PATENTS Number Country Date 626,865Great Britain 1949

